defragmenting c drive problem

I have Win 98 on a gateway solo 2150 and when trying to defrag, the system pauses on 2% and then struggles to get up to 4%. Goes back to 0 and starts again repeatedly never going above 4% even after 2 hours. The screen saver is switched off. Looking for details to no avail, blank screen. Never had problem on other kit. Does this indicate a mechanical fault, although all else works. Grateful for any help or opinions. Thanks Chiquita.

disk defragmentor doesnt like hard disk activity ,close any running programs or better to run it in safemode and allow a few hours to complete. Other commercial utility programs dont have this problem.